SRC/dorbdb5.f(3)

NAME
SRC/dorbdb5.f

SYNOPSIS

  Functions/Subroutines
subroutine dorbdb5 (m1, m2, n, x1, incx1, x2, incx2, q1, ldq1, q2, ldq2, work, lwork, info)
DORBDB5

Function/Subroutine Documentation

  subroutine dorbdb5 (integer m1, integer m2, integer n, double precision, dimension(*) x1, integer incx1, double precision, dimension(*) x2, integer incx2, double precision, dimension(ldq1,*) q1, integer ldq1, double precision, dimension(ldq2,*) q2, integer ldq2, double precision, dimension(*) work, integer lwork, integer info)

DORBDB5

Purpose:

    !>
    !> DORBDB5 orthogonalizes the column vector
    !>      X = [ X1 ]
    !>          [ X2 ]
    !> with respect to the columns of
    !>      Q = [ Q1 ] .
    !>          [ Q2 ]
    !> The columns of Q must be orthonormal.
    !>
    !> If the projection is zero according to Kahan's
    !> criterion, then some other vector from the orthogonal complement
    !> is returned. This vector is chosen in an arbitrary but deterministic
    !> way.
    !>
    !>

Parameters
    M1

    !>          M1 is INTEGER
    !>           The dimension of X1 and the number of rows in Q1. 0 <= M1.
    !>

    M2

    !>          M2 is INTEGER
    !>           The dimension of X2 and the number of rows in Q2. 0 <= M2.
    !>

    N

    !>          N is INTEGER
    !>           The number of columns in Q1 and Q2. 0 <= N.
    !>

    X1

    !>          X1 is DOUBLE PRECISION array, dimension (M1)
    !>           On entry, the top part of the vector to be orthogonalized.
    !>           On exit, the top part of the projected vector.
    !>

    INCX1

    !>          INCX1 is INTEGER
    !>           Increment for entries of X1.
    !>

    X2

    !>          X2 is DOUBLE PRECISION array, dimension (M2)
    !>           On entry, the bottom part of the vector to be
    !>           orthogonalized. On exit, the bottom part of the projected
    !>           vector.
    !>

    INCX2

    !>          INCX2 is INTEGER
    !>           Increment for entries of X2.
    !>

    Q1

    !>          Q1 is DOUBLE PRECISION array, dimension (LDQ1, N)
    !>           The top part of the orthonormal basis matrix.
    !>

    LDQ1

    !>          LDQ1 is INTEGER
    !>           The leading dimension of Q1. LDQ1 >= M1.
    !>

    Q2

    !>          Q2 is DOUBLE PRECISION array, dimension (LDQ2, N)
    !>           The bottom part of the orthonormal basis matrix.
    !>

    LDQ2

    !>          LDQ2 is INTEGER
    !>           The leading dimension of Q2. LDQ2 >= M2.
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array, dimension (LWORK)
    !>

    LWORK

    !>          LWORK is INTEGER
    !>           The dimension of the array WORK. LWORK >= N.
    !>

    INFO

    !>          INFO is INTEGER
    !>           = 0:  successful exit.
    !>           < 0:  if INFO = -i, the i-th argument had an illegal value.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 154 of file dorbdb5.f.

Author

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